Prerecorded Digital Portable Personal Stereo

ABSTRACT

This digital portable personal stereo comprises a housing containing a connection interface for connection to earphones; a digital memory immovably attached to the housing; an electronic circuit for accessing said memory; and a control interface for controlling said electronic circuit wherein that a encrypted audio content is prerecorded in the digital memory, and in that the portable personal stereo is adapted to prevent any other audio content from being written in the digital memory.

The present invention relates to a digital portable stereo, i.e. to aportable digital audio player.

In particular because of the development in the performance levels ofdigital memories and of audio data compression systems, there currentlyexist a large number of digital portable personal stereos.

In general, such a portable personal stereo includes a high-capacityinternal digital memory connected to a communications interface by meansof which it is possible to record audio content in the digital memoryfrom external equipment such as a computer.

Such a portable personal stereo also includes an electronic circuit forwrite and read accessing a memory, and a control interface that can beof various degrees of sophistication. Said interface is used forcontrolling operation of the portable personal stereo, and in particularfor controlling write and read accessing of the digital memory.

That applies, for example, to the digital portable personal stereodescribed in Patent Document US 2003/0016940.

Because of their complexity and of the need to interconnect them withother equipment, such portable personal stereos require advancedelectronic circuits; that poses problems in terms of cost, ofconsumption, and of sturdiness, in particular when the size of theportable personal stereos is small. Similarly, the communicationsinterfaces are elements that are costly and fragile.

An object of the invention is to solve those problems by means of adigital portable personal stereo that is simple, robust, andinexpensive.

To this end, the present invention provides a digital portable personalstereo comprising a housing containing:

-   -   a connection interface for connection to earphones;    -   a digital memory;    -   an electronic circuit for accessing said memory; and    -   a control interface for controlling said electronic circuit.

It is characterized in that a first audio content is prerecorded in thedigital memory, and in that the portable personal stereo is adapted toprevent any other audio content from being written in the digitalmemory.

Thus, the use of a memory having non-renewable audio content makes thecapacity of communicating with a computer or with any equivalentequipment unnecessary. This makes it possible, in particular, tosimplify the electronic circuit for accessing the memory and to simplifythe control interface, to increase mechanical robustness by omitting thecommunications interface, and to reduce power consumption.

As a result, the portable personal stereo makes it possible toconstitute a single-use portable personal stereo, or indeed a disposableportable personal stereo.

According to other characteristics of the invention:

-   -   the digital memory is accessible only via the electronic circuit        of the portable personal stereo, said electronic circuit being        suitable only for read accessing the digital memory;    -   the digital memory is accessible only via the electronic circuit        of the portable personal stereo, said circuit not having access        to any other audio content that might be recorded in the digital        memory;    -   said digital memory is a memory of the write-once type;    -   the portable personal stereo further comprises inhibit means for        inhibiting operation as a function of conditions of use;    -   the inhibit means are adapted to inhibit operation of the        electronic circuit for accessing the digital memory;    -   the inhibit means are adapted to inhibit operation of the        digital memory;    -   the inhibit means comprise a non-rechargeable battery that is        mounted to be an integral part of the housing and that powers        the portable personal stereo electrically;    -   the portable personal stereo is further provided with remote        control means for remotely controlling the inhibit means; and    -   the electronic circuit and the digital memory are formed in a        single electronic component.

The present invention can be better understood on reading the followingdescription given by way of example and with reference to theaccompanying figures, in which:

FIG. 1 is a block diagram showing the internal circuits of a portablepersonal stereo of the invention; and

FIG. 2 is an external view of the portable personal stereo of FIG. 1.

As shown in FIG. 1, the portable personal stereo mainly comprises ahousing 2 that is generally disc shaped, and that defines front and rearfaces and a cavity 4 in which electronic elements are placed.

In the cavity 4, the portable personal stereo includes an audio-contentdigital memory MEM 6. For example, this memory is a flash memorycontaining music files that are encoded in compliance with the “mp3”standard.

The memory 6 is prerecorded, i.e. an audio content is prerecorded duringa stage prior to use, such as a manufacturing stage.

The memory 6 is accessible via an electronic circuit 8 controlled by acontrol interface MMI 10 in order to deliver an audio signalcorresponding to the content of the memory 6 to two output ports OUT 12.

All of the elements of the portable personal stereo are powered by anelectrical power source such as a non-rechargeable battery 14, alsoplaced in the cavity 4.

The control interface 10 is connected to four buttons distributed aroundthe periphery of the housing 2 and to a central fifth button, as shownin FIG. 2. The functions of these buttons are known per se. For example,the central button 16 causes the audio content to be played continuouslyor causes such play to be paused, the buttons 18 and 20 respectivelycause the audio content to skip forwards or backwards, the button 22causes play to stop completely, or indeed causes the portable personalstereo to be switched off, and the button 24 makes it possible to adjustthe sound volume of the audio signal delivered to the output ports 12.

The portable personal stereo further comprises a pair of earphones 26connected to the ports 12. In the embodiment described, said earphones26 are secured to the housing 2 so that the portable personal stereo canbe used directly without requiring a preparatory operation such asplugging in the earphones.

Finally, in the example, the portable personal stereo is provided with atag 28 attached to the housing 2 and bearing information describing theaudio content of the memory 6. In a variant, the tag 28 bearsadvertising information.

The portable personal stereo of the invention is adapted to prevent anyother audio content from being written in the digital memory 6, i.e. toprevent the prerecorded audio content from being renewed.

In a first embodiment, the memory 6 is accessible only via theelectronic circuit 8 which is adapted only to read the content of thememory 6. Thus, the audio content of the memory 6 cannot be modified.

In a variant, the memory 6 is accessible only via the electronic circuit8 which does not have any replacement audio content. Thus, even if theelectronic circuit is adapted to write access the memory, no renewal ofthe audio content can be performed.

In these embodiments, the portable personal stereo does not have acommunications interface making it possible to access the memory 6 fromany other equipment for writing in the memory, and in particularequipment such as a computer. Thus, neither the electronic circuit 8 ofthe portable personal stereo nor any external equipment can write newaudio content in the memory.

In addition, the absence of any communications interface makes itimpossible to duplicate the content of the memory 6. Advantageously, thecontent of the memory is encrypted by means of an encryption key lodgedin a tamperproof memory of the portable personal stereo in order toprevent any duplication of the content even when the portable personalstereo is disassembled.

In another variant, the memory 6 is a write-once memory, such as aRead-Only Memory (ROM). Therefore, independently of the capacities ofthe electronic circuit 8 and of the existence of a communicationsinterface, the content of said memory cannot be modified.

Since the audio content of the digital memory cannot be renewed, theportable personal stereo is simple and easy to use. In addition, the useof an electronic circuit that is limited to reading, the absence of anycommunications interface, or indeed the use of a non-rewritable memoryreduces the cost of the portable personal stereo, and increases itselectronic and mechanical simplicity and its sturdiness.

In addition, in another embodiment of the invention, the portablepersonal stereo is further provided with means for inhibiting operationas a function of conditions of use such as the number of times it isused, the frequency of use, the time for which it is used, or some otherconditions.

In a first embodiment, the portable personal stereo is adapted so as toallow only a determined number of reads of the content of the memory.For example, once a maximum number of read accesses is reached, theaccess electronic circuit is inhibited and the content of the memory canno longer be read.

By way of a variant, when the maximum number of read accesses isreached, the digital memory is re-initialized. Optionally, theinitialization comprises a write access to the digital memory. Such awrite access does not constitute write access for writing a new audiocontent. The prerecorded audio content is overwritten with blank dataand not by another audio content.

In another embodiment, the battery of the portable personal stereo is anon-rechargeable battery that is mounted to be an integral part of thehousing 2 so that it cannot be replaced. Therefore, once the battery isdischarged, it is no longer possible to use the portable personalstereo. It is thus possible to limit the time for which the portablepersonal stereo is used by determining the quantity of energy stored inthe battery, and the consumption of the portable personal stereo.

Advantageously, the inhibit means include a remote control unit, e.g.operating by electromagnetic waves such as magnetic waves from asecurity gate. Thus, the portable personal stereo can be inhibited onpassing through such a gate, so that it operates only within a definedarea.

Other embodiments can also be devised.

In particular, in yet another variant, the memory and the readelectronic circuit are formed in the same component. This embodiment isparticularly advantageous for reducing the cost and the overall size ofthe portable personal stereo.

Naturally, the various embodiments described can be taken separately orin combination.

As a result of the above-described characteristics, the portablepersonal stereo of the invention is equipment that is simple tomanufacture and to use, that is compact, and that is stout. Thus, thisportable personal stereo is particularly adapted for single use or foruse for advertising purposes.

1. A digital portable personal stereo comprising: a housing; aconnection interface for connecting earphones to the stereo; a digitalmemory immovably attached to the housing; an electronic circuit foraccessing said memory; and a control interface for controlling saidelectronic circuit; wherein encrypted audio content is prerecorded inthe digital memory, and the portable personal stereo is adapted toprevent other audio content from being written in the digital memory. 2.A portable personal stereo according to claim 1, wherein the digitalmemory is accessible only via the electronic circuit of the portablepersonal stereo, said electronic circuit being suitable only for readaccessing the digital memory.
 3. A portable personal stereo according toclaim 1, wherein the digital memory is accessible only via theelectronic circuit of the portable personal stereo, said circuit nothaving access to other audio content that might be recorded in thedigital memory.
 4. A portable personal stereo according to claim 1,wherein said digital memory is a memory of the write-once type memory.5. A portable personal stereo according to claim 1, further comprisinginhibit means for inhibiting operation as a function of conditions ofuse.
 6. A portable personal stereo according to claim 5, wherein theinhibit means is adapted to inhibit operation of the electronic circuitfrom accessing the digital memory.
 7. A portable personal stereoaccording to claim 5, wherein the inhibit means is adapted to inhibitthe operation of the digital memory.
 8. A portable personal stereoaccording to claim 5, wherein the inhibit means comprises anon-rechargeable battery that is mounted such that it is an integralpart of the housing and, wherein, the battery powers the portablepersonal stereo electrically.
 9. A portable personal stereo according toclaim 5, further comprising a remotely activated control means forcontrolling the inhibit means.
 10. A portable personal stereo accordingto claim 5, wherein the electronic circuit and the digital memory areformed in a single electronic component.